Search results for "presbyopia"

Visual Performance of a Multifocal Toric Soft Contact Lens

2012

PURPOSE To evaluate the visual performance of the Proclear multifocal toric contact lens (CL; CooperVision, US) for both presbyopia and astigmatism correction. METHODS In this crossover study design, 20 presbyopic subjects with astigmatism were fitted in a random order with either Proclear multifocal toric CL or Proclear toric single vision distance CL (DCL) combined with reading spectacles. After 1 month, high-contrast distance visual acuity, near high-contrast visual acuity, distance contrast sensitivity (CS) under photopic and mesopic conditions without and with glare, near CS, defocus curve, and stereopsis were measured. Subjects were then refitted with the alternative correction, and t…

Stereoacuity After Refractive Lens Exchange With AcrySof ReSTOR Intraocular Lens Implantation

2009

Purpose: To evaluate stereoacuity before and after refractive lens exchange (RLE) with AcrySof ReSTOR intraocular lens (IOL) implantation. Methods: Stereoacuity was measured using the Titmus stereotest at 40 cm under photopic conditions (85 cd/m 2 ) before and after RLE with bilateral AcrySof ReSTOR Natural (SN60D3 model) implantation in 30 hyperopic eyes of presbyopes with low astigmatism (⩽1.00 diopter [D]). Stereoacuity measurements after implantation were compared with those found before surgery. Results: Stereoacuity was unchanged after RLE with pseudoaccommodative IOL implantation. In this population of non-cataractous hyperopes with excellent preoperative stereoacuity (46.42±1.36 se…

Effect of Multizone Refractive Multifocal Contact Lenses on Standard Automated Perimetry

2012

PURPOSE The aim of this study was to evaluate whether the creation of 2 foci (distance and near) provided by multizone refractive multifocal contact lenses (CLs) for presbyopia correction affects the measurements on Humphreys 24-2 Swedish interactive threshold algorithm (SITA) standard automated perimetry (SAP). METHODS In this crossover study, 30 subjects were fitted in random order with either a multifocal CL or a monofocal CL. After 1 month, a Humphrey 24-2 SITA standard strategy was performed. The visual field global indices (the mean deviation [MD] and pattern standard deviation [PSD]), reliability indices, test duration, and number of depressed points deviating at P<5%, P<2%, P<1%, an…

Comparison of the influence of corneo-scleral and scleral lenses on ocular surface and tear film metrics in a presbyopic population

2018

PURPOSE: To assess and compare the effect of the corneo-scleral lenses (C-ScL) and scleral lenses (ScL) on tear film parameters and central corneal thickness (CCT) in healthy presbyopic subjects. METHODS: Thirty subjects wore two contact lenses (CLs), randomly assigned, of neutral power, but of different diameters, 12.7mm (C-ScL) and 18mm (ScL) and being equal in the others parameters: material (HS100) and centre thickness (0.29mm). At baseline, 20min after insertion and at 8h, the tear meniscus area (TMA) and CCT was measured (with optical coherence tomography) as well as tear osmolarity. RESULTS: TMA revealed statistical differences for both lenses at 20min (p<0.001), and also at 8h (p=0.…

ReSTOR® Diffractive versus Array®2 Zonal-progressive Multifocal Intraocular Lens: a Contralateral Comparison

2007

PURPOSE. To evaluate near and distance visual performance after implantation of a diffractive multifocal intraocular lens (MIOL) (AcrySof ReSTOR ® ) or a refractive MIOL (Array ® 2) in bilateral cataract surgery. METHODS. In this prospective, comparative trial, 18 patients with bilateral cataract were selected to have lens surgery with asymmetric MIOL implantation. Eighteen eyes received ReSTOR MIOL and the 18 fellow eyes were implanted with Array 2. Five months after second lens implantation, main postoperative outcomes were uncorrected and distance corrected near visual acuities (VA). Secondary outcomes were distance VA and near acuity with power add, contrast sensitivity with and without…

Optical power distribution of refractive and aspheric multifocal contact lenses: Effect of pupil size

2015

Abstract Purpose To evaluate the power profile within the optic zone of different designs of multifocal contact lenses (CLs) and to analyze how the effect of pupil size could impact on their optical performance. Methods The optical power distribution within the optic zones of multifocal CLs was measured by the Nimo TR1504 (LAMBDA-X, Belgium). The multifocal CLs under study were the Acuvue Bifocal, the Acuvue Oasys for Presbyopia, the PureVision Multifocal and the PureVision 2 for Presbyopia. Each design was considered in all their available addition powers. All lenses had a nominal power of −3.0D. At the same time, three lenses of each model were considered and five consecutive readings of …

Opportunities and threats to contact lens practice: A global survey perspective

2021

Aim: To understand the views of contact lens (CL) practitioners across the globe regarding what they perceive as opportunities and threats in CL practice. Methods: A self-administered anonymised questionnaire, constructed in English and translated in six more languages, was distributed through reputed international professional bodies and academic institutions worldwide. The questionnaire included items on demographic characteristics, type of practice, and questions designed to explore practitioners’ perspective on the future of their CL practice over the next five years. Results: A total of 2408 valid responses were analysed. Multifocal CLs for presbyopia, CLs for myopia control, use of da…

Comfort visivo e indipendenza da occhiali con IOLs multifocali di nuova generazione: follow-up a 1 anno

2008

Power profiles in multifocal contact lenses with variable multifocal zone

2016

BACKGROUND The power profile of multifocal contact lenses has been demonstrated to report important information that could be used during the fitting process. The aim of this work is to describe the power profile of a recent set of gas permeable multifocal contact lenses as a function of the pupil radius. METHODS The measured multifocal contact lenses have a centre-distance design, and are available with five distance-vision diameters (XS, S, M, L and XL) and two different additions: Type A (up to +2.00 D) and Type B (up to +2.50 D). The optical device NIMO TR1504 (Lambda-X, Nivelles, Belgium) was used to obtain the power profile measurements. The optical lens power distribution as a functi…

Optical quality of rotationally symmetrical contact lenses derived from their power profiles.

2017

To present a methodology for evaluating the optical quality of rotationally symmetrical contact lenses (CLs) from a single power profile.Simulated rotationally symmetrical power profiles corresponding to different CLs designs (monofocal, two-zone center-near bifocal, and four-zone center-distance bifocal) were used to calculate the wavefront error profile by means of numerical integration. Then, each lens wavefront error profile was spun around the center to obtain the lens wavefront error surface. From the surface, monochromatic optical transfer functions (OTF), simulated images and the visual Strehl ratio based on the OTF (VSOTF) were obtained for different distances and pupil sizes (3 an…